Working principle of bridge push-pull circuit

The IffL circuit is a bridge push-pull output power amplifier circuit. The output stage in the OTL and OCL circuits consists
of two output tubes working in turn. When one output tube VTi is doing "push" output, the other output tube VT2 is
resting ; when the other output tube VT2 When doing "pull" output, the output tube VTi is resting. This means that "push" and
"pull" do not work at the same time. They only work in turn in the positive and negative half cycles of the signal , and at the same time they cross to form a complete
output signal . It can be imagined that if such a circuit can be formed: when the vTi tube is "pushed" at one end of the horn, another
tube VT4 is "pull" at the other end of the horn; when the VT2 tube is "pull" at one end of the horn, the other tube is "pushed" at one end of the horn. There is a VT3 tube
"pushing" at the other end of the speaker. See Figure 1-40. In this way, the output efficiency of the output circuit composed of "push" and "pull" can be
greatly improved. The bridge push-pull output power amplifier circuit is composed like this.